Blue-Green algae found in Blue Mesa Reservoir

Graphic credit: Climate Central

From the Associated Press via The Grand Junction Daily Sentinel:

The National Park Service says unsafe levels of a type of algae that can be harmful to humans have been found in the water of a central Colorado reservoir.

Park officials said they detected the presence of toxins that can be produced by algae blooms in water samples taken from Blue Mesa Reservoir.

The agency advised visitors to avoid contact with shallow waters in an area known as the Iola Basin and to avoid mats of algae throughout the reservoir.

The reservoir is part of Curecanti National Recreation Area west of Gunnison, Colorado.

Harmful blue-green algae is natural to the area but can spread quickly in warm, shallow water.

Forecast for Blue Mesa Reservoir = record low territory #ColoradoRiver #COriver #aridification

From The Colorado Springs Gazette (Liz Forster):

The Blue Mesa Reservoir, which feeds into the Colorado River, is at 39 percent capacity, according to the Bureau of Land Reclamation. The last time the reservoir west of Gunnison was at a similar level was in 1987, said Sandra Snell-Dobert, a spokeswoman for the Black Canyon of the Gunnison National Park and Curecanti National Recreation Area.

Soon, water levels are expected to drop to the point where launching and operating boats at most ramps won’t be possible, Snell-Dobert said

Low water levels and rising temperatures also have allowed for blue-green algae blooms. Although no direct environmental impacts have not been observed, some species of this algae can produce toxins that are harmful to dogs.

The Gunnison River Basin varied between 50 percent and 80 percent of its average snowpack this winter, hitting a low of 51.6 percent Dec. 20 and a peak of 79.81 percent April 20.

Other Colorado River reservoirs are facing similar shortages.

Lake Powell and Lake Mead in Arizona dropped to dangerous levels this week because of what scientists are calling the effects of the Colorado River’s worsening “structural deficit,” The Associated Press reported.

Lake Powell and Lake Mead hit 48 percent and 38 percent capacity, respectively.

The Colorado River basin, which feeds lakes Mead and Powell, has been drying out over the last two decades, scientists said. With the demands from farms and cities exceeding the available water supply, the strains on the river and reservoirs are being compounded by growing population, drought and climate change.

From Colorado Public Radio (Grace Hood):

The Colorado Division of Water Resources reports the basins were 50 percent full at the end of August, in contrast to last year’s 120 percent average capacity. The average for this time of year is about 82 percent.

The Yampa-White, San Juan-Dolores, Rio Grande, Gunnison and Colorado river basins are classified as being in either “moderate” or “severe drought.”

The Blue Mesa Reservoir near Gunnison on the Curecanti National Recreation Area, is near historic lows — it’s 39 percent full — and has closed almost all its boat ramps. Iola closed Thursday night, the Lake Fork ramp closes Monday. That will leave only the Elk Creek ramp on the reservoir’s north shore along Hwy. 50 open, said recreation area spokeswoman Sandra Snell-Dobert. “Elk Creek, the ramp will remain open as long as we can keep it open.”

The last time water levels were this low on the reservoir was in 1987, Snell-Dobert said. Blue Mesa usually only closes if there’s not enough staff or if the reservoir freezes. The reservoir levels now have also caused some abnormal boating hazards.

“Mostly it’s rocks that are becoming exposed as the water level decreases. There are a lot of rock promontories and islands, and those kinds of things that we haven’t seen in a long time,” she said. But despite the boating restrictions, Snell-Dobert said shoreline fishing, kayaking, canoeing and other hand-launched, non-motorized boating are still allowed at the reservoir.

Aspinall Unit operations update: Inflows to Blue Mesa Reservoir April-July = 35% of average

Blue Mesa Reservoir

From email from Reclamation (Erik Knight):

Releases from the Aspinall Unit will be decreased by 75 cfs on Sunday, September 9th. Releases are being decreased in order to bring flows in the lower Gunnison River closer to the baseflow target while conserving storage in Blue Mesa Reservoir. The actual April-July runoff volume for Blue Mesa Reservoir was 237,500 AF of inflow, which is 35% of average.

Flows in the lower Gunnison River are currently above the baseflow target of 890 cfs. River flows are expected to stay above the baseflow target for the foreseeable future.

Pursuant to the Aspinall Unit Operations Record of Decision (ROD), the baseflow target in the lower Gunnison River, as measured at the Whitewater gage, is 890 cfs for September.

Currently, diversions into the Gunnison Tunnel are 1000 cfs and flows in the Gunnison River through the Black Canyon are around 575 cfs. After this release change Gunnison Tunnel diversions will still be 1000 cfs and flows in the Gunnison River through the Black Canyon will be around 500 cfs.

Aspinall Unit operations update: 630 CFS in Black Canyon

Looking downstream from Chasm View, Painted Wall on right. Photo credit: NPS\Lisa Lynch

From email from Reclamation (Erik Knight):

Releases from the Aspinall Unit will be decreased by 100 cfs on Monday, July 23rd . Releases are being decreased to retain storage in Blue Mesa Reservoir while still reaching the baseflow target. A recent streamflow measurement has revealed that the Gunnison River at the Whitewater gage was flowing ~100 cfs higher than what the gage was reporting. The release adjustment at Crystal will bring those river flows back down closer to the baseflow target. The latest runoff volume forecast for Blue Mesa Reservoir projects 240,000 AF of inflow between April and July, which is 36% of average.

Flows in the lower Gunnison River are currently above the baseflow target of 900 cfs. River flows are expected to stay above the baseflow target for the foreseeable future.

Pursuant to the Aspinall Unit Operations Record of Decision (ROD), the baseflow target in the lower Gunnison River, as measured at the Whitewater gage, is 900 cfs for July. There is a provision in the EIS which allows the baseflow target to be reduced from 1050 cfs to 900 cfs when the content in Blue Mesa Reservoir is below 600,000 AF. The current content of Blue Mesa Reservoir is 427,000 AF and dropping.

Currently, diversions into the Gunnison Tunnel are 1050 cfs and flows in the Gunnison River through the Black Canyon are around 730 cfs. After this release change Gunnison Tunnel diversions will still be 1050 cfs and flows in the Gunnison River through the Black Canyon will be around 630 cfs. Current flow information is obtained from provisional data that may undergo revision subsequent to review.

Ouray “State of the River” meeting recap: “We can survive one bad drought” — Bob Hurford

Uncompahgre River Valley looking south

From The Telluride Daily Planet (Tanya Ishikawa):

[Bob] Hurford’s general sentiment about this year’s drought was shared by all who presented reports at the Ouray State of the Rivers meeting at the Ouray County 4H Event Center May 16. The presentations came two weeks after Gov. John Hickenlooper activated the Colorado Drought Mitigation and Response Plan for the agricultural sector in 34 of the state’s 64 counties, including San Miguel, Ouray, Montrose, and Delta counties…

Hurford explained that over half of the Rocky Mountains’ water supply is in its snowpack. As of April 1, Colorado’s snowpack was 68 percent of average and 64 percent of last year’s. Data maps show that the April 1 snowpack was between 50 percent and 69 percent for Ouray and Montrose counties, and below 50 percent for San Miguel County. Division 4, the eastern area around Gunnison, has the most snowpack; the San Juan Mountains have the least, with snowpack above Ridgway Reservoir at just 46 percent of average.

Colorado, Utah, Arizona and California had the lowest amount of precipitation in the U.S. this winter, and those four states — plus Nevada and New Mexico — had the highest temperatures from November 2017 to January 2018, according to statistics in Hurford’s report.

Data from reservoirs in October 2017 show that Colorado had one of its best years with close to 120 percent of average water levels statewide, 100 percent of average in Division 4 and around 116 percent of average in Ridgway Reservoir. Over the last two decades, reservoirs were at or above 100 percent for 11 years.

“We can survive one bad drought. Two bad droughts in a row and that gets us,” Hurford said.

Ridgway Reservoir Dam Superintendent Tony Mitchell, of Tri-County Water Conservancy District, showed National Weather Service forecast data that estimated January-April 1 flows into the reservoir at 88 percent of average in 2016, 111 percent in 2017 and 49 percent in 2018. For the period of April 1 through July, the main runoff season, flow estimates were 92 percent of average in 2016, 96 percent in 2017 and 40 percent in 2018.

Responding to a question about why the reservoir has looked lower than usual this spring, Tri-County Water Conservancy District Manager Mike Berry said late-season releases to the Uncompahgre Valley Water Users Association (UVWUA) were larger than usual last year, precipitation was low last summer and storage levels are kept lower than normal to avoid water spilling over the dam, which would send non-native fish into the Uncompahgre River, endangering the trout there.

UVWUA Manager Steve Andersen, who is also a director on the Colorado Water Conservation Board, said, “My association will be OK this year. There’s not as much water as we would like to have, but we will be able to make a crop this year.”

However, to ensure its downstream water users have enough water, the association in Montrose may have to put a call on water use later in the season, shutting headgates to irrigators upstream in Ouray County (who have junior water rights). Andersen does not expect to make a similar call on water on the upper Gunnison River side because of better snowpack, which should maintain higher flows there. He said the association would use that Gunnison water before resorting to a call on the Ouray side…

The last time that Ouray irrigators had to shut their headgates due to low stream flows and obligations to more senior water rights holders downstream was in 2012. That is when the Ouray County Water Users Association was founded…

With the drought conditions came concerns about wildfires, and Ouray and Montrose counties implemented Stage 1 Fire Restrictions on [May 21, 2018]. Stage 1 limits the areas where fires, smoking and spark-igniting activities can take place, according to the State of Colorado Department of Fire Prevention. Stage 2 adds more restrictions, while Stage 3 is the strictest, limiting entry into closed areas and setting fines as high as $10,000 for violators, or imprisonment for six months.

Aspinall unit operations update: Blue Mesa inflow forecast = 52% of 30 year average

Blue Mesa Reservoir

From email from Reclamation (Erik Knight):

The May 1st forecast for the April – July unregulated inflow volume to Blue Mesa Reservoir is 350,000 acre-feet. This is 52% of the 30 year average. Snowpack in the Upper Gunnison Basin peaked at 69% of average. Blue Mesa Reservoir current content is 496,000 acre-feet which is 60% of full. Current elevation is 7478.7 ft. Maximum content at Blue Mesa Reservoir is 829,500 acre-feet at an elevation of 7519.4 ft.

Based on the May 1st forecast, the Black Canyon Water Right and Aspinall Unit ROD peak flow targets are listed below:

Black Canyon Water Right
The peak flow target will be equal to 987 cfs for a duration of 24 hours.
The shoulder flow target will be 300 cfs, for the period between May 1 and July 25.

Aspinall Unit Operations ROD
The year type is currently classified as Dry.
There is no peak flow target in a Dry year category
Baseflow targets will continue to be met throughout the year.

Releases from the Aspinall Unit will be increased by 400 cfs on Monday, May 14th in order to allow the Black Canyon water right to be met. Flows on the North Fork of the Gunnison River are also predicted to be near peak levels at this time. The resulting flow on the lower Gunnison River at the Whitewater gage is estimated to be around 2500 cfs. On Tuesday, May 15th, releases from the Aspinall Unit will be decreased by 400 cfs to return river flow to the pre-peak level.

Pursuant to the Aspinall Unit Operations Record of Decision (ROD), the baseflow target in the lower Gunnison River, as measured at the Whitewater gage, is 890 cfs for May and 1050 cfs for June.

Currently, diversions into the Gunnison Tunnel are 1000 cfs and flows in the Gunnison River through the Black Canyon are 600 cfs. During the 1 day peak flow Gunnison Tunnel diversions will still be 1000 cfs and flows in the Gunnison River through the Black Canyon will be around 1000 cfs. River flows will return to 600 cfs the day after the peak flow. Current flow information is obtained from provisional data that may undergo revision subsequent to review.

Aspinall Unit operations update: Gunnison Tunnel diverting for the season

Gunnison Tunnel via the National Park Service

From email from Reclamation (Erik Knight):

Releases from the Aspinall Unit have been increasing over the last couple weeks as diversions to the Gunnison Tunnel have begun. So far these release changes have kept the flows in the Gunnison River through the Black Canyon around 630 cfs. Diversions into the Gunnison Tunnel are expected to increase again this week. This time releases from Crystal Dam will remain unchanged and Gunnison River flows will decrease accordingly. It is expected that river flows will decrease by 100-200 cfs this week. Currently snowpack in the Upper Gunnison Basin is at 72% of normal. The latest runoff volume forecast for Blue Mesa Reservoir projects 360,000 AF of inflow between April and July, which is 53% of average.

Flows in the lower Gunnison River are currently above the baseflow target of 890 cfs. River flows are expected to stay above the baseflow target for the foreseeable future.

Pursuant to the Aspinall Unit Operations Record of Decision (ROD), the baseflow target in the lower Gunnison River, as measured at the Whitewater gage, is 890 cfs for April and May.

Currently, diversions into the Gunnison Tunnel are 620 cfs and flows in the Gunnison River through the Black Canyon are around 630 cfs. By the end of the week Gunnison Tunnel diversions could be in the 700 to 800 cfs range and river flows could be in the 400 to 500 cfs range. Current flow information is obtained from provisional data that may undergo revision subsequent to review.